John Anthony Blair

In Logical Self-Defense, Johnson and I introduced the criteria of acceptability, relevance and sufficiency as appropriate for the evaluation of arguments in the sense of reasons offered in support of a claim. These three criteria have been widely adopted, but each has been subjected to a number of criticisms; and also 30 years of research have intervened. How do these criteria stand up today? In this paper I argue that they still have a place in argument analysis and evaluation, but in much-modified roles.

Informal logic began in the 1970s as a critique of then-current theoretical assumptions in the teaching of argument analysis and evaluation in philosophy departments in the U.S. and Canada. The last 35 years have seen significant developments in informal logic and critical thinking theory. The paper is a pilot study of the influence of these advances in theory on what is taught in courses on argument analysis and critical thinking in U.S. and Canadian philosophy departments. Its finding, provisional and much-qualified, is that the theoretical developments and refinements have had limited impact on instruction in leading philosophy departments.